This invention relates to padlocks, and more particularly to the latch mechanism which functions to lock and release the padlock shackle.
All padlocks, whether of the permutation type, the key operated type, or of the combination permutation and key operated type, necessarily include a latch mechanism which, at one time functions to hold the padlock shackle in its locked position, and at another time functions to release the shackle for movement to its open position. The latch mechanism has become more or less standardized in that a spring-biased latch bolt slidably carried in a pivoted rocker engages a notch formed in the padlock shackle. This engagement of the latch bolt in the shackle notch prevents upward movement of the shackle to its open position.
Means well known and established in the art are utilized to disengage the latch bolt from the shackle notch by pivoting the rocker, as in permutation type padlocks, or by sliding the latch bolt into the rocker, as in key operated padlocks. Such disengagement permits upward movement of the shackle to its open position whereupon the latch bolt is slidably returned to its original disposition. Downward movement of the shackle to a locked position involves moving the shackle against the latch bolt and sliding the latch bolt back into the rocker until the shackle notch is aligned with the latch bolt, whereupon the latch bolt slides into engagement with the shackle notch.
As described, after the latch mechanism functions to unlock the padlock, the spring-biased latch bolt returns to its original disposition automatically and will then interact with the shackle to relock the padlock without subsequent manipulation of the padlock key or the padlock combination dial. Unfortunately, the advantages afforded by the spring-biased latch bolt are somewhat offset by the disadvantage that such a latch bolt is subject to forceful and manipulative tampering designed to open this type of padlock. A sharp blow against the padlock casing with simultaneous or repetitive tapping of the padlock shackle in a particular manner can cause the latch bolt to move into the rocker sufficiently to permit upward movement of the shackle, thus "springing" or opening the padlock.
The present invention is designed to overcome the tampering aspect of this type of padlock by providing means to limit or restrict the sliding movement of the latch bolt in the rocker.